Beryllium-aluminum-copper composites



March 12, 1968 E. 1. LARSEN ETAL 3,373,002

BERYLLIUM-ALUMINUM-COPPER COMPOSITES Filed May 11, 1967 ALUMINUM- COPPER PHASE DIAGRAM WEIGHT PER CENT ALUMINUM IO I5 3O 4O 5O 6O 8090 1200 I I II |||I||||| 1100K 37 IOOO O U5 soo------ A ---X 0: D

700 M a 62A Cu) e If 600 59I. A E 2 53- /548 b-dAl g I 82.7 97.5 or (A1) 500 F (620)(943) 400 339525 SQI 2 e FIG fl 0 IO 20 3o 0 so so 70 so I00 ATOMIC PER CENT ALUMINUM FIGZ JFJME. 3

INVENTORS EARL I LARSEN RICHARD H. KROCK BY CLINTFORD R. JONES ATTORNEY United Stats Patent ABSTRACT OF THE DILOSURE A two phase composite material whose microstructure consists of beryllium dispersed in an aluminum-copperberyllium solid solution alloy matrix was produced by liquid phase sintering pressed powder mixtures of beryllium, aluminum and copper.

The present invention relates to ductile composites of beryllium-aluminum-copper which can be sintered to substantially theoretical density and to means and methods for providing said composites through liquid phase sintering.

Liquid phase sintering differs from the several other types of sintering techniques in that the sintering of the compact is carried out in the presence of a liquid phase. Liquid phase sintering encompasses raising the temperature of the compressed powder metal constituents of beryllium, aluminum and copper to a temperature wherein a predetermined amount of the liquid phase appears. In the liquid phase, one of the metal constituents, the solid, is progressively dissolved in the other metal constituents, the liquid. However, the quantities of these constituents are such that, at equilibrium, some solid phase always exists. It is thought that the liquid wets the solid so as to bring about favorable surface energies existing between the liquid and the solid thereby permitting solution into the liquid phase.

However, heretofore, when beryllium-aluminum-copper composites were fabricated in accordance with known liquid phase sintering techniques, it was found that the solid beryllium expelled the liquid aluminumcopper-beryllium 'alloy from the compact during liquid phase sintering. It is thought that the unfavorable surface energy equilibrium causing expulsion of the liquid aluminum-copper-beryllium alloy is due to a tough, tenaciousfilm of beryllium oxide which is present on each particle of beryllium.

The present invention prevents the expulsion of the liquid aluminum-copper-beryllium alloy from the specimen by using an agency to intervene in the sintering stage. The agency either breaks down the oxide fil-m on the beryllium or segregates to the metal oxide interface and lowers the surface energy of the liquid metal with respect to the beryllium oxide film so that the liquid metal progressively dissolves the solid metal.

The agency can be called a fluxing agent or flux, however, the agent has other characteristics which assist in wetting beryllium so as to surround the beryllium with a ductile envelope phase of aluminum-copperberyllium alloy matrix metal thereby avoiding the expulsion of the liquid from the specimen.

Beryllium has several desirable physical features which make it attractive for a variety of commercial applications such as lightweight gears, lightweight fasteners, airplane parts or the like. However, beryllium has one major drawback which has seriously limited its commercial acceptance, that is, beryllium is inherently brittle at room temperature.

The lack of ductility of beryllium is attributed to the 3,373,002 Patented Mar. 12, 1968 See crystal structure of beryllium which is hexagonal close packed. During deformation, the basal planes of the hexagonal close packed structure, being the easiest to slip, are aligned along the working direction. Since slip is crystallographically difficult perpendicular to the basal plane, the ductility of beryllium perpendicular to the primary fabrication direction is practically nonexistent.

Several possible solutions have been advanced in an attempt to make beryllium metal sufficiently ductile so as to permit a widespread commercial acceptance of beryllium. Cross-rolling and cross-forging have been suggested as fabrication methods which might enhance the ductility of beryllium. These fabrication techniques reduced the number of basal planes along the direction of rolling and resulted in improved ductility. However, the degree of improvement was far from satisfactory. The fact remained that beryllium must be classified as brittle at room temperature even utilizing the aforementioned method when ductility perpendicular to the fabrication temperature is considered. In addition, the abovernentioned technique would not be feasible where the fabrication is, by nature, solely along one axis such as swaging, drawing and extrusion.

In recent years, attention has been directed to the fabrication of beryllium alloys not having the inherent brittleness of beryllium itself but possessing various outstanding properties of the metal such as, for example, low density combined with high strength. It is thought that U.S. Patent 3,082,521 fabricated the first ductile beryllium alloy by rapidly cooling the part from a temperature at which it was liquid. However, the beryllium content of the alloy was not in excess of 86.3 atomic percent which is approximately 33 weight percent of the alloy. Although the beryllium alloy was ductile, the density of the alloy was in excess of that of aluminum and about equal to that of titanium.

It has also been suggested that beryllium alloys might be fabricated by pressing and sintering a mix of metal powders. However, such a method results in expulsion of the matrix metal or metals from the beryllium specimen and the eventual freezing of the matrix metal or metals into globs on the surface of the solid specimen. It is thought that the expulsion of the matrix metal or metals is due to the surface energies of the solid beryllium and the various liquids formed. The unfavorable surface energy equilibrium is believed to be due to a tough, tenacious film of beryllium oxide which is present on each particle of beryllium.

A means and method have been discovered for preparing a composite of beryllium, aluminum and copper containing about 50 to percent, by weight, of beryllium, about 14.2 to about 50.0 percent, by weight, aluminum and a trace to about 2.85 percent, by weight, copper, thereby producing a composite having a density about the same as or less than that of aluminum, having high strength, and having ood ductility. The ductility is due to the resulting microstructure of the composite.

By surrounding the beryllium particles with a ductile envelope phase, a composite is formed where, under load, the beryllium is so constrained by the ductile phase that it and the ductile phase deform continuously.

The 85 percent, by weight, beryllium composite showed a considerable amount of particle contiguity and would represent, it is thought, an upper limit on the percent by weight of beryllium contained by the composite. A decrease in beryllium content below 50 percent would raise, it is thought, the density value of the composite to a value of little interest.

Alkali and alkaline earth halogenide agents such as lithium fluoride-lithium chloride or the like in a determined ratio are utilized to segregate to the solid interface of the beryllium particle and either break down the film on the particle of beryllium and/ or alter the liquidsolid surface energy in the system.

Therefore, it is an object of the present invention to provide a ductile beryllium-aluminum-copper composite having low density and high strength.

A further object of the present invention is to provide a ductile composite of beryllium-aluminum-copper in which beryllium is the predominate ingredient.

' Yet still another object of the present invention is to provide a means and method of producing a ductile composite of beryllium-aluminum-copper wherein the microstructure consists of beryllium particles surrounded by a ductile envelope phase of an aluminum-copperberyllium alloy matrix metal.

Yet another object of the present invention is to provide a ductile composite of beryllium-aluminum-copper containing about 50 to 85 percent, by weight, beryllium, about 14.2 to 50.0 percent, by weight, aluminum and a trace to 2.85 percent, by weight, copper.

Another object of the present invention is to provide a ductile beryllium-alu-minum-copper composite having a matrix phase that is heat treatable.

Another object of the present invention is to provide a composite of beryllium-aluminum-copper that may be sintered to substantially theoretical density.

Another object of the present invention is to provide a ductile composite of beryllium-aluminumcopper containing about 50 to 85 percent, by weight, beryllium and the remainder an alloy of aluminum-copper consisting of about 95.5 percent, by Weight, aluminum, the remainder copper.

Yet another object of the present invention is to provide a means and method whereby a ductile berylliumaluminum-copper composite may be successfully fabricated in both a practical and economical manner.

A further object of the present invention is to provide an agent which eliminates the expulsion of an alloy of aluminum-copper beryllium from a beryllium specimen.

Still another object of the present invention is to provide an agent to promote liquid phase sintering of a beryllium-aluminum-copper mixture.

Still another object of the present invention is to provide alkali and alkaline earth halogenide agents used in the fabrication of a beryllium-aluminum-copper composite.

, A further object of the present invention is to provide a lithium fluoride-lithium chloride agent for promoting liquid phase sintering in a beryllium, aluminum and copper mix.

Yet still another object of the present invention is to provide a lithium fluoride-lithium chloride agent wherein the constituents are used in a predetermined ratio.

The present invention, in another of its aspects, relates to novel features of the instrumentalities of the invention described herein for teaching the principal object of the invention and to the novel principles employed in the instrumentalities whether or not these features and principles may be used in the said object and/or in the said field.

With the aforementioned objects enumerated, other objects will be apparent to those persons possessing ordinary skill in the art. Other objects will appear in the following description and appended claims. The invention resides in the novel combination of elements and in the means and method of achieving the combination as hereinafter described and more particularly as defined in the appended claims.

In the drawings:

FIGURE 1 is a phase diagram for binary alloys of aluminum-copper.

FIGURE 2 is a photomicrograph of a beryllium speciment illustrating an aluminum-copper-beryllium matrix metal expelled from the specimen by the forces of surface energy of solid. beryllium and the aluminum-copperberyllium liquid.

FIGURE 3 is an enlargement showing about a 70 percent, by weight, beryllium, about 28.65 percent, by weight, aluminum, remainder copper composite illustrating beryllium particles surounded by a ductile envelope phase of an aluminum-copper-beryllium alloy.

Generally speaking, the means and method of the present invention relates to a ductile beryllium-aluminumcopper composite fabricated by liquid phase sintering to substantially theoretical density. The composite contains about 50-85 percent, by weight, of beryllium about 14.2 to 50.0 percent, by weight aluminum and a trace to about 2.85 percent, by weight, copper.

The method of producing the beryllium-aluminumcopper composite by liquid phase sintering comprises the steps of mixing predetermined portions of powder beryllium and powder alloy of aluminum-copper or aluminum powder and copper powder with a predetermined portion of an agent selected from the group consisting of alkali and alkaline earth halogenides. The portions are pressed in a die to form a green compact. The compact is then heated to the sintering temperature of beryllium. At this temperature the agent provides a favorable surface energy equilibrium between the beryllium and the aluminumcopper alloy so that the alloy progressively dissolves the beryllium at the sintering temperature so as to form an aluminum-copper-beryllium alloy matrix. Thereafter, the beryllium-aluminurn-copper composite may be heat treated and rapidly quenched so as to preserve the heat treating teinperature structure and the aluminum is supersaturated with copper. Precipitation or ageing may be carried out followed by air cooling to room temperature.

More particularly, the method of the present invention comprises mixing powder beryllium of about 50-85 percent, by weight, with a powder alloy of aluminum-copper or the elemental powders of aluminum and copper. An agent of lithium fluoride-lithium chloride is in about 0.5 to 2.0 percent, by weight, of the total metal additions is mixed with the beryllium or with the beryllium and the alloy powder or elemental powder. The constituents of the agent are in about a one to one ratio by weight. The beryllium, the alloy powder or elemental powder, and the agent are pressed so as to form a green compact. The green compact is heated in a non-oxidizing atmosphere such as argon at a temperature of about 700 C. to about l C. At the aforementioned temperatures, the agent provides a favorable surface energy equilibrium between the beryllium and the alloy so that the aluminum-copper alloy progressively dissolves the beryllium. The microstructure of the resultant composite consists of beryllium particles surrounded by a ductile envelope phase of an aluminum-copper-beryllium alloy matrix metal. The alloy is sintered to substantially its theoretical density. The alloy may be specially heat treated and rapidly quenched so that the heat treating temperature structure is preserved and the aluminum is supersaturated with copper. Precipitation or ageing may be carried out followed by air cooling to room temperature.

In carrying out the present invention, a beryllium base compact is fabricated by any suitable means such as powder metallurgy techniques. A suggested method utilizing this technique is to mix beryllium powder with an agent of equal parts of lithium fluoride-lithium chloride. The milling is carried out for about 1 hour using ceramic balls. Thereafter, a powder alloy of aluminum-copper or the elemental powders are ball mill mixed with the beryllium and the agent for an additional hour. The blended and mixed powders are compacted to form a green compact by accepted metallurgical methods such as by compacting within the confines of a die in a hydraulic or an automatic press or by placing the powder in a rubber or plastic mold and compacting in a hydrostatic press. The green compact is sintered in a non-oxidizing atmosphere such as argon or the like at a temperature of about 700 C. to about 1100 C. It is seen that the range of the sintering temperatures is below the 1277 C. melting point temperature of the beryllium and is above the 660 C. melt ing point temperature of the aluminum-copper alloy. The aluminum-copper alloy will dissolve smaller beryllium particles and will dissolve the surfaces of the larger beryllium powder particles so as to surround the remaining beryllium particles with a ductile envelope phase of an aluminum-copper-beryllium alloy during sintering of the compact. The resultant composite of beryllium-aluminumcopper had a density of about 98 percent of theoretical density.

Composites containing about 50 to 85 percent, by weight, of beryllium, and the remainder an alloy of aluminum-copper were successfully fabricated. The agent prevented the expulsion of the liquid aluminum-copper-beryllium alloy from the compact by the forces of surface energy, that is, prevented the formation of very fine rounded droplets of the aluminum-copper-beryllium alloy on the surface of the beryllium specimen. FIGURE 2 shows a beryllium specimen having on the surface thereof an expelled alloy 21 of aluminum-copper-beryllium. Specimens from which the aluminum-copper-beryllium alloy has been expelled have gross porosity and as a result are weak, brittle, and of little commercial value.

The composition of the agent utilized is about 50 parts, by weight, of lithium fluoride to about 50 parts, by weight, of lithium chloride. The agent provides an action, such that, upon heating or sintering of the pressed powder mix to the temperature at which the liquid phase forms, expulsion of the melt from the specimen is eliminated. Furthermore, it was found that solution of the beryllium into the alloy was enhanced as evidenced by the rounded particles of beryllium in the microstructure.

It was found that the amount by weight of lithium fluoride-lithium chloride agent should exceed 0.5 percent, by weight, of the total of all metal additions. It would appear that the optimum range of the agent is from about 0.5 percent to about 2.0 percent, by weight, of the total of all metal additions. It is believed that the quantity of lithium fluoride-lithium chloride agent required is related to the amount necessary to cover the total beryllium surface area. Hence, the minimum amount of agent needed would be a function of the surface area of the beryllium powder. The utilization of lithium fluoride-lithium chloride agent in other than equal parts is possible. It is thought, however, that an equal parts mixture achieves optimum results.

It was found during sintering that substantially 100 percent of the fiuxing agent was lost during sintering. This result would seem to indicate that the fiux entered into a chemical reaction whereon it decomposed and then volatilized and/ or the flux volatilized as lithium fluoridelithium chloride.

By using the methods of the present invention and the lithium fluoride-lithium chloride agent, compacts were fabricated containing up to 85 percent, by weight, of beryllium, the remainder an alloy of aluminum-copper without the use of pressure during sintering. The composite was sintered to about 93.5 percent of its theoretical density by a single sinter and achieved about 98 percent of theoretical density by a repress and an intermediate re-liquid phase sinter for about 1 hour. Using powder beryllium having a particle size of 20 microns or finer and using ceramic balls to blend the powder metals and the agent resulted in a composite having a high density. The good strength and low density characteristics of the beryllium were retained and the resulting beryllium-aluminum-copper composite possessed good ductility.

Thus. by substantially surrounding the beryllium parti cles with a ductile envelope phase of an aluminum-copper-beryllium alloy matrix metal, the beryllium and the matrix metal deform continuously under load.

An aluminum copper phase diagram is illustrated in FIGURE 1. Copperstrengthens aluminum by solid solution hardening and precipitation hardening. The theory of the deformation of dispersed particle composite materials states that ductility in such a composite will be enhanced when the constrained flow stress of the matrix phase can be made as equal as possible to the flow stress of the dispersed particles. Hence, copper is used to harden aluminum. Once the composite has been cooled to room temperature, the effectiveness of the copper is further brought into play by a subsequent heat treatment. It was found that heat treating the composite at about SOD-550 C. for about 12 hours is sufficient to completely dissolve all the copper in the aluminum. The composite is rapidly quenched into a satisfactory medium such as water or the like, such that the high temperature structure is preserved and the aluminum is supersaturated with copper. Hence, the selutionizing treatment contains all the copper in solution. The copper can be precipitated out of the supersaturated solid solution as a zeta phase increasing the strength of the aluminum-copper matrix. An advantage of the beryllium-aluminum-copper composite is that the matrix phase is heat treatable.

Attention is directed to FIGURE 3, wherein a photomicrograph of about 500 magnifications shows a composite of 30 percent, by weight, aluminum-copper alloy in beryllium after being etched by any suitable etching means such as a dilute solution of ammonium hydroxide and hydrogen peroxides. The areas 10 are beryllium particles. The areas 11 are the aluminum-copper-beryllium alloy surrounding the beryllium particles.

It will be recognized by those-skilled in the art that minor additions of other metals maybe added to the matrix of the composite to improve one or more of the physical properties such as machinability, deoxidation, and the like. For example, an addition of a trace to about 1 percent, by weight, of either bismuth manganese, or lead to the composite improves machinability thereof. An addition of a trace to about 1 percent, by weight, of magnesium to the composite will improve the deoxidation property of the composite.

Example 1 shows the expulsion of the liquid from a beryllium specimen and Examples 2-13 are illustrative of the preparation of beryllium-aluminum-copper composites by liquid phase sintering.

Example 1 Expulsion of the liquid aluminum-copper-beryllium alloy from the solid beryllium specimen occurs during liquid phase sintering when the agent of lithium fluoridelithium chloride is not used in the preparation of a beryllium-aluminum-copper composite.

A mixture of about percent, by weight, of beryllium having a particle size of 200 mesh or finer was ball mill mixed with about 30 percent, by weight, of an alloy of aluminum-copper or the elemental powder of suitable particle size. The alloy contained about 95.5 percent, by weight, aluminum, and about 4.5 percent, by weight, copper. The milled mixture was pressed by any suitable means such as by an automatic press at a suitable pressure to provide a green compact sturdy enough to be handled. It was found that pressures of from about 15,000 to 20 ,000 pounds per square inch resulted in a green compact having a density from about 50 to 60 percent of theoretical density and sufiiciently strong to be handled. Sintering of the compact was carried out in an argon atmosphere at about 1100" C. for about 1 hour. This technique, due to the surface energies of the solid beryllium and the liquid formed, resulted in the expulsion of the liquid from the specimen and its eventual freezing into rounded globs on the surface of the specimen as shown in FIGURE 2.

Example 2 A composite of about 70 percent, by weight, beryllium, about 28.65 percent, by weight, aluminum, and the remainder copper.

A mixture of about 70 percent, by weight, of beryllium powder having a particle size of 200 mesh or finer was ball mill mixed using ceramic balls with about 30 percent, by weight, of an alloy of aluminum-copper powder of suitable particle size. The alloy contained about 95.5 percent, by weight, aluminum and about 4.5 percent, by weight, copper. Also ball mill mixed with the beryllium and alloy powders was about 1.0 percent, by weight, of the total metal additions equal parts of an agent of lithium fluoride-lithium chloride. Mixtures of the beryllium and alloy powders were also prepared with the agent having 0.5 and 2.0 percent, by weight, of the total metal additions using varying ratios of lithium fluoride-lithium chloride. The milled mixture was pressed by any suitable means such as by an automatic press at a suitable pressure to provide a green compact sturdy enough to be handled. It was found that pressures of from about 15,000 to 20,000 pounds per square inch resulted in a green compact having a density of from 50 to 60 percent of theoretical density and sufficiently strong to be handled. Sintering of the compact was carried out in an argon atmosphere at about 1100 C. for about 1 hour. A second press followed by a second sinter at about 1100 C. for about 1 hour raised the density of the composite to about 98 percent of theoretical density. The composite was heat treated at about 550 C. for about 1 hour so as to completely dissolve all the copper into the aluminum. The composite was then rapidly quenched so that the heat treating temperature structure was preserved and the aluminum was supersaturated with copper. The copper can be precipitated from the supersaturated solid solution as a zeta phase (see FIGURE 1) thereby precipitation hardening the composite by heating the composite to about 160 C. for about 3 to 5 hours.

Example 3 A composite of about 70 percent, by weight, beryllium, about 28.65 percent, by weight, aluminum, and the remainder copper.

A mixture of beryllium powder having a particle size of micron or finer was ball mill mixed with about 2.0 percent, by weight, of the total metal additions equal parts of an agent of lithium fluoride-lithium chloride. The milling was carried out with ceramic balls for about 1 hour. Thereafter, an alloy powder of about 95.5 percent, by weight, aluminum and 4.5 percent, by weight, copper was ball mill mixed with the beryllium for about 1 hour. Ceramic balls were used to mix the powders. The beryllium constituted about 70 percent, by weight of the blended powders and the alloy powder constituted about percent of the blended powders. Mixtures of the beryllium and alloy powders were also prepared with the agent having 0.5 and 1.0 percent, by weight, of the total metal additions using varying ratios of lithium chloride to lithium fluoride. The milled mixture was pressed by any suitable means such as by an automatic press at a suitable pressure to provide a green compact sturdy enough to be handled. It was found that pressures of from about 15,000 to 20,000 pounds per square inch resulted in a green compact having a density of from about 50 to 60 percent of theoretical density and sufficiently strong to be handled. Sintering of the compact was carried out in an argon atmosphere at about 800 C. for about 1 hour. Another composite was prepared using the above procedure but sintering for /2 hour. Both cornposites were repressed and resintered. Each composite was heattreated at about 500 C. for about 1 hour so as to dissolve the copper into the aluminum. Each composite was then rapidly quenched so that the heat treating temperature structure was preserved and the aluminum was supersaturated with copper. It was found that the composite sintered for 1 hour had a density of about 98 percent of theoretical density and the composite sintered for about /z hour had a density substantially the same. A sintering temperature as low as 700 C. may be used but it is preferred that a Sintering temperature of 800 C. or above be used.

Example 4 A composite of about 70 percent, by weight, beryllium, 28.65 percent, by weight, aluminum, and the remainder copper.

The procedure of Example 3 was followed using about 70 percent, by weight, beryllium, about 28.65 percent, by weight, aluminum powder, and the remainder copper powder. Individual composites were prepared using 0.5, 1.0 and 2.0 percent, by weight, of the total metal additions.

Example 5 A composite of about 70 percent, by weight, beryllium, 28.65 percent, by weight, aluminum, and the remainder copper.

The procedure of Example 3 was followed using about 70 percent, by weight, beryllium powder, mixed with about 30 percent, by Weight, of an alloy powder of aluminum-copper. The alloy contains about 95.5 percent, by weight, aluminum and about 4.5 percent, by weight, copper. Individual composites were prepared using 0.5, 1.0 and 2.0 percent by weight of the total metal additions of the agent lithium fluoride-lithium chloride in equal proportions and in unequal proportions at a temperature of about 1100 C. for /2 hour and 1 hour using the aforementioned procedure.

Example 6 A composite of about 50 percent, by weight, beryllium, about 50 percent, by weight, aluminum, and a trace of copper.

The procedure of Example 3 was followed using 50 percent, by weight, beryllium powder, mixed with about 50 percent, by weight, of an alloy powder of aluminumcopper. The alloy contains about percent, by weight, aluminum and a trace of copper. Individual composites were prepared using 0.5, 1.0 and 2.0 percent by weight of the total metal additions of the agent lithium fluoridelithium chloride at temperatures of about 800, 900, 1000 and 1100 C. for /2 hour and for 1 hour using the aforementioned procedure.

Example 7 A composite of about 50 percent, by weight, beryllium, about 47.15 percent, by weight, aluminum, and the remainder copper.

The procedure of Example 3 was followed using 50 percent, by weight, beryllium powder, mixed with about 47.15 percent, by weight, aluminum powder and the remainder copper powder. Individual composites were prepared using 0.5, 1.0 and 2.0 percent by weight of the total metal additions of an agent lithium fluoride-lithium chloride at temperatures of about 800, 900, 1000, 1100 C. for /2 hour and for 1 hour using the aforementioned procedure.

Example 8 A composite of about 60 percent, by weight, beryllium, 38.2 percent, by weight, aluminum, and the remainder copper.

The procedure of Example 3 was followed using 60 percent, by weight, beryllium powder, mixed with about 40 percent, by weight, of an alloy powderof aluminumcopper. The alloy contains 95.5 percent, by weight, aluminum and 4,5 percent, by weight, copper. Individual composites were prepared using 0.5, 1.0 and 2.0 percent by weight of the total metal additions of the agent lithium fluoride-lithium chloride at temperatures of about 800, 900, 1000 and 1100 C. for /2 hour and 'for 1 hour using the aforementioned procedure.

Example 9 A composite of about 75 percent, by weight, beryllium, 23.9 percent, by weight, aluminum, and the remainder copper.

The procedure of Example 3 was followed using 75 percent, by Weight, beryllium powder, mixed with about 25 percent, by weight, of an alloy powder of aluminumcopper. The alloy contained 95.5 percent, by weight, aluminum and 4.5 percent, by weight, copper. Individual composites were prepared using 0.5, 1.0 and 2.0 percent by weight of the total metal additions of the agent lithium fluoride-lithium chloride at temperatures of about 700, tures of about 800, 900, 1000 and 1100 C. for /2 hour and 1 hour using the aforementioned procedure.

Example A composite of about 85 percent, by weight, beryllium, 14.2 percent, by weight, aluminum, and the remainder copper.

The procedure of Example 3 was followed using 85 percent, by weight, beryllium powder, mixed with about percent, by weight, of an alloy powder of aluminumcopper. Individual composites were prepared using 0.5, 1.0 and 2.0 percent by weight of the total metal additions of the agent lithium fluoride-lithium chloride at temperatures of about 800, 900, 1000 and 1100 C. for /2 hour and 1 hour using the aforementioned procedure.

The present invention is not intended to be limited to the disclosure herein, and changes and modifications may be made in the disclosure by those skilled in the art without departing from the spirit and scope of the novel concepts of this invention. Such modifications and variations are considered to be within the purview and scope of this invention and the appended claims.

Having thus described our invention, we claim:

1. A ternary metal composite consisting essentially of about -85 percent, by weight, of beryllium, and the remainder an alloy of aluminum-copper.

2. A ternary metal composite according to claim 1, wherein said beryllium particles are surrounded by a matrix of an alloy of aluminum-copper-beryllium.

3. A metal composite according to claim 1, wherein said composite consisting essentially of about 14.2 to 50 percent, by weight, aluminum, and a trace to about 2.85 percent, by weight, copper.

4. A metal composite according to claim 1, wherein said alloy of aluminum-copper consisting essentially of about 95.5 percent, by weight, aluminum, the remainder copper.

References Cited UNITED STATES PATENTS 2,072,067 2/1937 Donahue -l50 3,322,512 5/1967 Krock 29182.2 3,322,514 5/1967 Krock 29-1822, 3,323,880 6/1967 Krock 29-l82.2

L. DEWAYNE RUTLEDGE, Primary Examiner. A. STEINER, Assistant Examiner. 

